1. Field of the Invention
The present invention relates to an image blur correction device for optically correcting the image blur of a camera, and an imaging device using same.
2. Description of the Background Art
An image blur is a disturbance of a photographed image that is generated by the micro-vibration of the camera when an image is photographed by the camera. When a camera is handled by human hands, for example, this micro-vibration is generated by a human body motion of which cycle is relatively long, or by a tremor of human hands and fingertips of which cycle is relatively short. An image blur correction device for a camera, which has the merit of allowing a night shot without a tripod by the slow shutter function is more and more frequently installed in a camera. An optical correction feature, which optically corrects image blur, has a particular advantage in terms of resolution over an electronic correction feature, which electronically corrects image blur, therefore the former is the standard as an image blur correction device. One optical image blur correction method is an image blur correction method that displaces such optical components as a correction lens disposed among lenses and an image sensing element disposed in the camera main body in a direction perpendicular to the optical axis.
For example, Japanese Patent Application Laid-Open No. 2008-233385 (D1) discloses an image blur correction device which corrects image blur at the lens side. In the image blur correction device disclosed in document D1, the correction lens is supported by a holder and is inserted into the optical system, and a coil, that is an actuator for displacement, is displaced at one end of the holder, and a ball is disposed at the other end, where a drive force is generated with a permanent magnet disposed in a fixed position by energizing the coil, so that the correction lens displaces in a direction perpendicular to the optical axis.
A problem of the above configuration is that if the ball is not inserted in the assembly step, then it is difficult to detect this absence since the clearance that is lost by this omission is small (the unit itself is small). Even if the absence of the ball can be detected, this requires a difficult inspection procedure, which means that the absence of a ball is unnoticed until optical performance is checked. In other words, this detection is possible only when defocus and blur are generated at the ball side in test photographing. Because of this, a defective unit may enter into subsequent steps, causing problems latter. In the case of image blur correction at the main body side, an image blur correction mechanism is disposed in the sensor unit of the image sensing element, but if a tilt (optical axis) adjustment mechanism is disposed between the image blur correction mechanism, in which the sensor unit is installed, and a lens barrel, the above mentioned defocus and blur, due to the absence of a ball, are corrected by the tilt adjustment, and the camera having this defective unit may be shipped.